TROJ_KRYPTIK.AAAA

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan drops the following copies of itself into the affected system:

• %User Temp%\rundll11-.txt

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other System Modifications

This Trojan deletes the following files:

• %User Temp%\.exe
• %User Temp%\vSGV1BFKRX.ini
• %User Temp%\Lbd3Oz8qQ1.ini

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "%User Temp%\file.exe"

Dropping Routine

This Trojan drops the following files:

• %User Temp%\invs.vbs
• %User Temp%\tmp.exe
• %User Temp%\msJIA0LDcO.ini
• %User Temp%\ceAHeMxQrv.ini
• %User Temp%\file.exe

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Trojan connects to the following possibly malicious URL:

• http://onyearmi.{BLOCKED}u.com/php/index.php?{random characters}
• {BLOCKED}.161.96
• {BLOCKED}.164.249

This report is generated via an automated analysis system.